Cyclic Elastoplastic Large Displacement Analysis of Cold-formed Steel Box Columns under Combined Action of Axial and Bidirectional Lateral Loading

This paper deals with the cyclic elastoplastic large displacement analysis of cold-formed steel box columns under combined action of axial and bidirectional lateral loading. Cold-formed steel box columns are very useful in highway bridge pier construction as they offer flexible space requirement and provide speedy construction. Behavior of cold-formed steel box columns under earthquake-induced loads is rather complicated as earthquakes occur in an oblique direction. However, modern seismic design philosophies have been based on the behavior of structures under independent actions of uni-directional loading in orthogonal directions. In this study, inelastic cyclic behavior of steel columns subjected to constant axial force together with simultaneous bi-directional cyclic lateral loads is investigated using an advanced finite element analyses procedure. Several types of linear and non-linear idealized loading patte rns are employed to check the strength and ductility. The effects of important structural parameters and loading history on the behavior of cold-formed thin-walled steel box columns are examined using the proposed procedure